Commitments (Narrative) (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Commitments [Abstract]
Commitments to fund investments in notes receivable	$ 0

Commitments to Fund Investments In Notes Receivable

No definition available.

Name:	cik0001640982_CommitmentsToFundInvestmentsInNotesReceivable
Namespace Prefix:	cik0001640982_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant